Grade 12.9 Black Cup Head Hexagonal Reverse/Left Thread Screws M5 M6 M8 M10 M12 DIN912 Left Tooth Bolt Anti-tooth Screw Black hexagon screw Left hand screw Left tooth bolt Inverted tooth screw Hexagon screw Cylindrical head snail Cup head screw Grade 12.9 Black Cup Head Hexagonal Reverse/Left Thread Screws M5 M6 M8 M10 M12 DIN912 Left Tooth Bolt Anti-tooth Screw